PTL 1 discloses a structure in which a multilayered substrate is formed by stacking a plurality of substrates with metal mainly including Ag used at a through hole and inner layer conductors. A solder paste is spread over the through hole formed in the substrate disposed on the surface of the multilayered substrate, and electronic components, such as chip resistors, are mounted on the solder paste so as not to form a wiring pattern on the uppermost surface. In PTL 1, the electronic components forming a circuit is connected to a flow rate sensor element with inner layer conductors. A circuit board is a ceramic substrate with the uppermost surface thereof being protected by glass.